/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 1997-2009 Sun Microsystems, Inc.  Portions Copyrighted 2008 Richard Schilling.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
 * identifying information: "Portions Copyrighted [year]
 * [name of copyright owner]"
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 * Contributor(s): Richard Schilling (coderroadie@gmail.com)
 *
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
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 */

package javax.mail.internet;

import javax.mail.*;
import com.cognition.android.activation.*;
import java.io.*;
import java.net.UnknownServiceException;
import com.sun.mail.util.PropUtil;

/**
 * A utility class that implements a DataSource out of
 * a MimePart. This class is primarily meant for service providers.
 * 
 * @see javax.mail.internet.MimePart
 * @see javax.activation.DataSource
 * @author John Mani
 */

public class MimePartDataSource implements DataSource, MessageAware {

    /**
     * The MimePart that provides the data for this DataSource.
     * 
     * @since JavaMail 1.4
     */
    protected MimePart part;

    private MessageContext context;

    private static boolean ignoreMultipartEncoding = PropUtil.getBooleanSystemProperty(
            "mail.mime.ignoremultipartencoding", true);

    /**
     * Constructor, that constructs a DataSource from a MimePart.
     */
    public MimePartDataSource(MimePart part) {
        this.part = part;
    }

    /**
     * Returns an input stream from this MimePart.
     * <p>
     * This method applies the appropriate transfer-decoding, based on the
     * Content-Transfer-Encoding attribute of this MimePart. Thus the returned
     * input stream is a decoded stream of bytes.
     * <p>
     * This implementation obtains the raw content from the Part using the
     * <code>getContentStream()</code> method and decodes it using the
     * <code>MimeUtility.decode()</code> method.
     * 
     * @see javax.mail.internet.MimeMessage#getContentStream
     * @see javax.mail.internet.MimeBodyPart#getContentStream
     * @see javax.mail.internet.MimeUtility#decode
     * @return decoded input stream
     */
    public InputStream getInputStream() throws IOException {
        InputStream is;

        try {
            if (part instanceof MimeBodyPart)
                is = ((MimeBodyPart) part).getContentStream();
            else if (part instanceof MimeMessage)
                is = ((MimeMessage) part).getContentStream();
            else
                throw new MessagingException("Unknown part");

            String encoding = restrictEncoding(part.getEncoding(), part);
            if (encoding != null)
                return MimeUtility.decode(is, encoding);
            else
                return is;
        } catch (MessagingException mex) {
            throw new IOException(mex.getMessage());
        }
    }

    /**
     * Restrict the encoding to values allowed for the
     * Content-Type of the specified MimePart. Returns
     * either the original encoding or null.
     */
    private static String restrictEncoding(String encoding, MimePart part)
            throws MessagingException {
        if (!ignoreMultipartEncoding || encoding == null)
            return encoding;

        if (encoding.equalsIgnoreCase("7bit") || encoding.equalsIgnoreCase("8bit")
                || encoding.equalsIgnoreCase("binary"))
            return encoding;	// these encodings are always valid

        String type = part.getContentType();
        if (type == null)
            return encoding;

        try {
            /*
             * multipart and message types aren't allowed to have
             * encodings except for the three mentioned above.
             * If it's one of these types, ignore the encoding.
             */
            ContentType cType = new ContentType(type);
            if (cType.match("multipart/*") || cType.match("message/*"))
                return null;
        } catch (ParseException pex) {
            // ignore it
        }
        return encoding;
    }

    /**
     * DataSource method to return an output stream.
     * <p>
     * This implementation throws the UnknownServiceException.
     */
    public OutputStream getOutputStream() throws IOException {
        throw new UnknownServiceException("Writing not supported");
    }

    /**
     * Returns the content-type of this DataSource.
     * <p>
     * This implementation just invokes the <code>getContentType</code> method
     * on the MimePart.
     */
    public String getContentType() {
        try {
            return part.getContentType();
        } catch (MessagingException mex) {
            // would like to be able to reflect the exception to the
            // application, but since we can't do that we return a
            // generic "unknown" value here and hope for another
            // exception later.
            return "application/octet-stream";
        }
    }

    /**
     * DataSource method to return a name.
     * <p>
     * This implementation just returns an empty string.
     */
    public String getName() {
        try {
            if (part instanceof MimeBodyPart)
                return ((MimeBodyPart) part).getFileName();
        } catch (MessagingException mex) {
            // ignore it
        }
        return "";
    }

    /**
     * Return the <code>MessageContext</code> for the current part.
     * 
     * @since JavaMail 1.1
     */
    public synchronized MessageContext getMessageContext() {
        if (context == null)
            context = new MessageContext(part);
        return context;
    }
}
